Oxygen Vacancy Promoted O2 Activation over Perovskite Oxide for Low-Temperature CO Oxidation

IF 13.1 1区化学 Q1 CHEMISTRY, PHYSICAL

ACS Catalysis Pub Date : 2019-09-18 DOI:10.1021/acscatal.9b02408

Ji Yang, Siyu Hu, Yarong Fang, Son Hoang, Li Li, Weiwei Yang, Zhenfeng Liang, Jian Wu, Jinpeng Hu, Wen Xiao, Chuanqi Pan, Zhu Luo, Jun Ding, Lizhi Zhang, Yanbing Guo*

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引用次数: 212

Abstract

The insights on the primary active oxygen specie and its relation with oxygen vacancy is essential for the design of low-temperature oxidation catalysts. Herein, oxygen vacancy-rich La_0.8Sr_0.2CoO₃ with an ordered macroporous structure was integrated on the commercial ceramic monolith in large scale without additional adhesives via a facile in situ solution assembly. The constructed macropores not only contributed to the oxygen vacancy generation in catalyst preparation but also facilitated favorable mass transport during catalytic process. Combined with theoretical investigations and EPR, O₂-TPD, H₂-TPR observations, we revealed that monatomic oxygen ions (O^–) are the primary oxygen active specie for perovskite oxide. And molecular O₂ is more favorably adsorbed and activated on surface oxygen vacancies via a one electron transfer process to form monatomic oxygen ions (O^–), thus boosting richness of active O^– and the low-temperature oxidation of CO. Different with the preferential Eley–Rideal (E-R) mechanism on pristine LSCO surface, Langmuir–Hinshelwood (L-H) mechanism, in which O^– reacts with adsorbed CO to finish the oxidation reaction, was more favorable on the oxygen vacancy rich surface. Our work here elucidates the primary active oxygen specie as well as its origin over perovskite oxides and paves a feasible pathway for rational design of high-performance catalysts in heterogeneous reactions.

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氧空位促进钙钛矿氧化物上O2的低温CO氧化活性

了解初级活性氧种类及其与氧空位的关系对设计低温氧化催化剂具有重要意义。本文通过原位溶液组装，将具有有序大孔结构的富氧空位La0.8Sr0.2CoO3大规模集成在商业陶瓷整体上，无需额外的粘合剂。所构建的大孔不仅有利于催化剂制备过程中氧空位的生成，而且有利于催化过程中质量的传递。结合理论研究和EPR、O2-TPD、H2-TPR观察，我们发现单原子氧离子(O -)是钙钛矿氧化物的主要氧活性物质。与原始LSCO表面上优先的Eley-Rideal (E-R)机制不同，在富氧空位表面上，O -与吸附的CO发生反应完成氧化反应的Langmuir-Hinshelwood (L-H)机制更有利于O2分子的吸附和活化，形成单原子氧离子(O -)，从而提高活性O -的丰富度，促进CO的低温氧化。我们的研究阐明了钙钛矿氧化物中活性氧的主要种类及其来源，为非均相反应中高性能催化剂的合理设计铺平了可行的途径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

ACS Catalysis CHEMISTRY, PHYSICAL-

CiteScore

20.80

自引率

6.20%

发文量

1253

审稿时长

1.5 months

期刊介绍： ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels. The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.